The fourth generation (4G) Long Term Evolution (LTE) standard is based on packet-switched Internet Protocol (IP) networking. User equipments (UEs) that are 4G LTE-compliant are configured to provide voice communication capabilities over 4G LTE networks using a packet-based protocol, such as the voice over LTE (VoLTE) protocol. The VoLTE protocol dedicates a particular speech codec for encoding and decoding audio, thereby allowing two or more people to talk to each other over a mobile telephony network using respective user equipment (UE). The 3rd Generation Partnership Project (3GPP) standard specifies speech codecs that are to be used in the provisioning of VoLTE services over mobile telephony networks. Adaptive Multi-Rate (AMR) codec is one such speech codec that supports eight narrow band (i.e., 300 to 3400 Hertz (Hz)) speech coding modes with respective bit rates between 4.75 and 12.2 kilobits per second (kbps). AMR Wideband (AMR-WB) is another speech codec that supports nine wide band speech coding modes with respective bit rates between 6.6 and 23.85 kbps. Table 1, below, provides the nine wide band speech coding modes supported by AMR-WB:
TABLE 1AMR-WB Speech Coding Modes# of Bits inAMR-WB Coding ModeBit Rate (kbps)20 millisecond frame06.613218.85177212.65253314.25285415.85317518.25365619.85397723.05461823.85477
AMR-WB provides improved speech quality, as compared to its narrowband counterpart (AMR), due to a wider frequency band of 50 to 7000 Hz, which allows for new wideband audio technologies, such as high definition (HD) voice (sometimes referred to as “HD calling”). HD voice provides clearer-sounding calls and a decrease in background noise (e.g., street traffic, wind, crowd noise, etc.) as compared to non-HD calling. Notwithstanding the carrier implementation of HD voice, however, not all VoLTE traffic is actually encoded/decoded using the available AMR-WB codec. This is primarily due to the fact that not all UEs are capable of utilizing the AMR-WB codec for speech encoding/decoding. For example, a VoLTE capable UE may call a landline or an older, legacy UE that is incapable of handling HD calling using the AMR-WB codec. As a result, some communication sessions end up being “renegotiated” to a narrowband speech codec (e.g., AMR) in order to establish a voice communication session. Carriers (or cellular network operators) that provide HD voice services typically lack insight into the proportion of their customers' calls that actually utilize AMR-WB (HD voice), which is a potentially valuable insight.